The desire to develop renewable and carbon-neutral fuels encourages the utilization of solar-generated electricity for water splitting to produce hydrogen.  We have previously reported an anodically-deposited heterogeneous water oxidation catalyst formed by the oxidation of molecular organometallic iridium precursors.  The resulting heterogeneous material is an effective catalyst for the water oxidation half-reaction.  Recently, we found that the deposition of a thin catalyst layer not visible to the human eye is robust and gives a low overpotential for water oxidation.  However, this overpotential was found to increase in unbuffered electrolyte at high pH.  To overcome this limitation, thin layers of catalyst were studied under various buffering conditions using a rotating disk electrode (RDE) to achieve non-diffusion limited conditions.  Some buffers were observed to change the Tafel-plot behavior of the catalyst, an effect which suggests a possible change in the rate-limiting step of the water oxidation reaction.

Optimization of a highly-active heterogeneous iridium-based water-oxidation catalyst

243rd National Meeting (2012)

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